Localização de falhas estruturais utilizando metodos de ajuste de modelos por matriz otima

AUTOR(ES)

Carlson Antonio Mendes Verçosa

DATA DE PUBLICAÇÃO

1995

RESUMO

The service life of a structural element is, in general, shortened when there is a reduction of the load capacity to which it was originally designed. In structural dynamics this reduction is referred to as a structural fault. Structural faults cause the deterioration of the structure and, therefore, information about their existence and location may be used to ensure its integrity. The basic hypothesis implied here is that structural faults cause changes in the p~ysical properties of the structure which, in turn, affect its natural frequencies and mode shapes. In this work, fault localization is done using optmal-matrix update methods which involve the analytical mass and stiffness matrices of the original structure and the natural frequencies and mode shapes of the flawed structure. The analytical model is obtained using the finite element method and the experimental data is obtained using experimental modal analysis. A new model update method is presented as well as a modification of Alvar Kabe s method, which incorporates the concept of pseudo-sparsity caused by force cancellation when assembling the stiffness matrix. Numerical simulation and experimental results are used to validate the proposed method and to investigate the influence of the modal base truncation in the fault localization processo It is shown that, in the absence of noise, the methods that adjust the stiffness matrix element-by-element reproduce exact1y the stiffness coefficients and preserve the matrix sparsity. This is not the case when using the methods called global. Nevertheless, both types of methods allow the exact localization of the structural faults. In the presence of noise in the experimental modes, the global methods have a better performance in the process of localizing structural faults

ASSUNTO(S)

localização de falhas (engenharia) dinamica estrutural analise modal

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